Short answer: no. Long answer: yes, but only if you boil it first. Barley malt will naturally have some wild yeast and/or bacteria on it, and mashing temperatures aren't high enough to kill them all. So you *could* store it in the fridge, but I wouldn't wait more than maybe 12 hours.

I sorta agree with Mike. That little amount of malt would make very little difference. Just steeping would not lend as much character as a mash would, however, it would certainly add more goodness than pils extract alone. Probably the lesser of 2 evils - I'd think that there'd be too much of a chance of spoilage if you mash and not boil quickly thereafter. And just steeping would be less time consuming.